prime.c

    #include <stdio.h>
    int main()
    {
        int n, i, flag = 0;
        printf("Enter a positive integer: ");
        scanf("%d", &n);
        for(i = 2; i <= n/2; ++i)
        {
            // condition for nonprime number
            if(n%i == 0)
            {
                flag = 1;
                break;
            }
        }
        if (n == 1) 
        {
          printf("1 is neither a prime nor a composite number.");
        }
        else 
        {
            if (flag == 0)
              printf("%d is a prime number.", n);
            else
              printf("%d is not a prime number.", n);
        }
        
        return 0;
    }